Tailoring the Porous Hierarchy of Titanium Phosphates

Abstract

First hierarchical titanium phosphate (TiPO) materials with multiple porosities of different lengths (meso-macroporous and meso-macro-macroporous) were synthesized by the self-formation process. The further tuning of the porous hierarchy by using the poly(ethylene oxide) surfactant technique was demonstrated. The macroporous structure (50-160 nm in size) of TiPO with mesoporous walls could be self-formed in the absence of any templatable agents, including surfactant molecules. On the basis of spontaneous structurization, the addition of a small quantity of nonionic poly(ethylene oxide) surfactant (e.g., 5%) led to an improvement in macroporosity in abundance and in regularity with a slight enlargement in macropore sizes to 80-250 nm. Interestingly, a secondary, larger macropore system with parallel channels 500-1000 nm in size was generated when the synthesis was performed with moderately increasing the content of surfactant (10%), giving rise to an unprecedented trimodal meso-macro-macroporous structure. A uniform three-dimensional co-continuous macroporous structure with accessible wormhole-like mesoporous walls was synthesized by using the higher content of surfactants. This is a direct demonstration of tailoring the porous hierarchy of different lengths integrated in one solid body by fine-tuning the self-formation process and the participation of surfactant. The synthesized hierarchical titanium phosphates possess interesting optical and acidic properties, which should be significant for large application potential from catalysis and separation to electrochromic devices, fuel cells, and bioactive materials.

Nanostructured Titania–Diphosphonate Hybrid Materials with a Porous Hierarchy

“…The interfacial microemulsion polymerization of titanium phosphonate sols and titanium oxo clusters rendered the formation of mesostructured titania-phosphonate nanorods with homogenously attached organophosphonate units, [14] which further aggregated along with the microemulsions to give a hierarchical macroporous structure ( Figure 3). In this process, phase separation might take place in the growing aggregates of Tiwww.eurjic.orgHEDP-based mesophases and water/alcohol domains, [15,16] leading to the creation of huge, sporadic macrochannels in hierarchical macroporous networks. Figure 4 shows the N 2 adsorption-desorption isotherms and the corresponding pore size distribution curves of the hybrid Ti-HEDP and pure titania.…”

Study of photocatalytic activity of Cd-doped mesoporous nanocrystalline TiO2 prepared at low temperature

“…. Compared with the binding energy of pure TiO 2 (459 eV for Ti2p 3/2 and 464.8 eV for Ti2p 1/2 ) [34], the binding energy of Ti2p decreases after Cd 2? ion doping, which implies that TiO 2 crystal lattices are modified by Cd atoms.…”

Organic‐Additive‐Assisted Synthesis of Hierarchically Meso‐/Macroporous Titanium Phosphonates

“…Noticeably, a hierarchy with three different pore-size lengths (mesopores, small macropores, and large macropores) is integrated into one www.eurjic.orgsolid body of A-CD, which is of great importance in the design of structured catalysts for one-pot reactor processes. [32] The pH value of the reaction solution is one of the most important factors that determine the textural properties of the final products. In order to investigate the effect of acidity on the porosity of the synthesized materials, NaOH solution was used to adjust the pH of the synthesis mixture from Ͻ1 to 3, 7, and 10, and the mesoporosity of A-CD obtained at the different pH values was tested by determining the N 2 sorption (Figure 7).…”

“…[30,31] Moreover, careful examination of these SEM micrographs reveals that the pore wall of the large macropores in A-CD are separated by smaller spherical pores with the size of 50-100 nm, which thereby forms a two-scaled macroporous structure (Figure 1e). It is reminiscent of the hierarchically meso-/macroporous titanium phosphates synthesized in the presence of the polyethylene oxide surfactant Brij 56, [32] which indicates that the surfactant molecules are not necessary for the formation of the macrochannels, but the addition of a small amount of β-cyclodextrin could lead to the presence of secondary small-scaled macropores. The TEM images present a particulate morphology between the macrochannels of the samples (Figure 2).…”